In a message broadcast at the Liberals' campaign launch on Sunday night, Mr Morrison said Mr Coe's strategy to spur economic growth by lowering taxes was the right plan for Canberra.

"Liberal governments federally and all around Australia are about delivering lower taxes, better services," the Liberal Prime Minister said.

"What makes that happen is our strong belief that if you grow your economy and focus on the things that grow your economy then you can make the promises that matter and that is to guarantee the essential services that Australians rely on.

"Alistair Coe, he understands that and that's why as leader of the Canberra Liberals he is putting forward at this election a positive plan. A positive plan that would see taxes lowered and that would see services improved."

In what represents his first involvement in the ACT election campaign, Mr Morrison drew parallels between the federal government's tax cuts and Mr Coe's plan to freeze residential rates and cut car registration fees. The prime minister said the policies were in keeping with the "core Liberal principal" of allowing people to keep more of the money they earned.

"The reason that I know that Alistair Coe can deliver lower taxes and better services is because he is a Liberal, because that is what Liberal governments do," Mr Morrison said.

"Federally, we have reduced taxes and vastly improved services that Australians rely on by growing our economy, rather than increasing taxes."

Mr Coe has been questioned almost daily on the campaign trail about the how the Canberra Liberals would pay for their expensive package of election promises without cutting public sector jobs or services, or racking up more debt.

In response, the Opposition leader has maintained that the polices could be funded by growing the ACT's population and, in turn, its revenue "pie". The plan hinges on stopping the flow of Canberrans across the border to NSW, which Mr Coe believed could be achieved by lowering the cost of living in the nation's capital.

In his message, Mr Morrison backed the strategy and said the commitments put forward by Mr Coe weren't "empty promises".

"By making Canberra more affordable for people to live here, we will grow the pie to generate more tax revenue and that enables the government to be able to afford the commitments that Alistair has laid out," Mr Morrison said.

In contrast to the address federal Labor leader Anthony Albanese delivered at ACT Labor's campaign launch, which attacked Mr Coe's stance on social issues, Mr Morrison's message didn't make a single reference to the Liberal leader's opponent - Chief Minister Andrew Barr.

The prime minister did take a veiled swipe at the long-serving Labor government, saying if Mr Coe became chief minister he would have the opportunity to "turn things around" as Liberal premiers have done in other states.